Hot-air furnace



June 5, 1928. 1,672,247

F. A. CONRAD HOT AIR FURNACE Original Filed Oct. 4, 1926 3 Sheets-Sheet, 1

46 .52 s2 42 42 4a 2a 3o as t '12 56 9 I 3 4 z ----I9 3 -32 32 I6 I Inventor: frank Conrad. 59 74 M4 2 form e gs.

June 5, 1928. 1,672,247

' F. A. CONRAD HOT AIR FURNACE Original Filed 0013.4, 1926 a sheets-sheet 2 In ven-Lor':

June 5, 1928.

F. A. CONRAD HOT AIR FURNACE Original Filed Oct. 4, 1926 3 Sheets-Sheet 3 Inventor: flank Conrad M M/ m izzornegs.

Patented June 5, 1928 UNITED sTzn-us PATENT-7' OER-ICE.

v FRANK A. CONRAD, or sr. PAULLMINNESOTA. I

, 1 nor-AIR FUR A E.

Application filed October 4, 926, Serial No. 139,390. Renewed April 1 s, 1928. f

-My invention relates to hot air furnaces,

' and an object is to provide a furnace of this type in which the heat going to the various rooms is equally distributed or automatically equalized so that all of the rooms in the building will receivetheir proper share of heat regardless of. conditions tending to cause a greater 'fiow of heat to someof the 'rooms than to other rooms. Another, ob-f j ect is to provide for moistening and cleaning' the heated air which is supplied to the rooms. Another object is to conserve heat and prevent waste of fuel. Another object. is to centralize and produce an even draft through the fire or grates. Another object is to cause the gases, smoke, and flame to rise to the top of the combustion chamber and then be deflected downwardly before passing to the exit leading to the chimney which action tends to burn the gases more completely and to force the flame into direct contact with the radiatingsurface of the furnace. I 'The full objects and. advantages of my invention will appear in connection with the detailed description thereof, and the novel features of my inventive idea will be particularly pointed out in'the claims.

In the accompanying drawings which illustrate a practical embodiment of myinvention,

Fig. 1 is a view of the furnace in central vertical section. Fig. 2 is-a top plan view. Fig. 3 is a view in horizontal section on the line 33 of Fig. 1 Fig. 4 is a plan view of the top members of the casings looking at the inside thereof before these members are.

below the grate as usual. The casing 12 is v closed at its topto produce acombustion chamber 19. Surrounding and spaced from the furnace casing 12 is an inner casing 20 formed in sections as shown infFig. 5, the sections having inturned flanges 22 which engage each other to form a series of radially extending parti-tions between the casings 12 and 20. l A band 24 secured. around the sections hold them in place. Thecasing 20 is provided with aconical top 26 which has a depending flange fitting over the upper end of the casing, this top being provided withopenings 28 fitted with short outwardly extending pipe sections 30.. Concentrically spaced around the casing 20 is an. intermediate casing '32 which is provided with a conical top 34-riveted thereto.

the sections 30 to provide the annular-openings 43. concentrically spaced around the intermediate casing 32 is-anouter casing 44 which is provided with a conical top 46 having openings, the edges of which are closely engaged by 'thehot air pipes 42. The top member'46 while of conical shape ingeneral does not extend to an apex butat its center is provided with an upwardly extending an- The space between the apices of the conical tops nular flange. 48 for receiving the end of a I cold air supply pipe 50. The top members 26 and 34 are maintained in properly spaced relation by the interposed insulating material 36. "The top members 34 and 46 are maintained in properly spaced relation by interposed spacing sleeves 52-through which bolts 54 pass. These bolts also pass through the three top members so that the top structure is held together and; may be handled as a unit with the pipe sections 30 secured in place while the members42 ofthe hot air pipes may afterward be secured inrplace or they may'consist of comparatively short pipe sections for convenience in handling. The outer casing 44 if desired may consist of horizontal sections riveted together as shown in Fig. 1 with'the joints'between the sections and the joint betweenthecasing and the top member 46 covered bybands .56.

Charging doors'58 and 60 are'hinged to the outer casing .adjacent suitable openings which extend-through all of the casings. A smoke pipe 62 is shown secured to a smoke fiue with which the furnace is provided.

. The member 64: passes through openings in the casings 20, 32, and 44 andhas its inner end telescopically engaging the outer end of the member 66. The inner end of the latter is turned so as toextend directly upward and is located centrally in the combustion chamber l.9 wi1th,rel-ation to the surrounding wall thereof. The fine member 6.6 may be supported in the manner illustrated. in Fig. 1, whi-ch shows two bolts 68; and adjustablysecured together, the bolt 68- being attached to: themen'iber 66 and the bolt 70- extendigngthrough the casing 12' and; througln a: flange on. the member 64. i As will be understood particularly fron'i. Fig.v 5, partition members are secured to: the upper ends of the partition flanges 22', the members T2 separating the ,spacein the-top member-2.6 below the plate 38 intocompa-rtments which constitute extensions-of the compart ments. formed by the flanges 22'. The outer casing ld has its-lower: end disposedin' such manner as to make a tight seal at the bot-- tom while the casings 2.0 and 352' stop short:

of the bottom; As shown in F ig-. 11, the lower. end of the casingel fitstightly upon the outerwall of an annular water trough 74s resting: upon the floor. This trough: is made in sections with a gap adjacent the ash-pit door 1-8,.the sections being secured together by a screw-threaded sleeve 7 6 so as: to be in. communication with each other. Water. may be, supplied to the, trough thi'zough a pipe 7 6; connected: with; thewater SYSEQDTEHlCl? having a: shut-off valve 7'8fCOI1- trolled by azfloat in thetrough.

The operation and advantages of; my in.- vcntionuwilll be understood in connectionwith the foregoing description. -Gold or fresh air supplied in any suitable manner enters through: theinlet pipe 50 and passes downwardly between the outer casing 44 and the intermediate casing 32! and after coming into contact with the, water inthe trough 74 passes upwardly between" the fhrx nace casing 12-andthe inner. casing 20 through thecompartments formed by the rzulialpartitions constituted by thefianges 22andthe members 7 2. The space'between the two casings 20 and 32:constitutes an insulating chamber. The air. when it passes over'the' water in the trough, takes up moistureand is freed from impurities. From the compartments surroi'mding the furnace casing,- the: heated and moist'ened." air passes throughthe short; pipe s'ec'tionszSO into the hot airipipes 42which supply. hot air to the variousrooms of; the building; Under ordinary. workingconditions ofzthe furnace, the pipes 42 .will' receive allor the greater por tion oftheir supply ofair through theshort pipe sections 30. However, if conditions arise so that one or more of the pipes 42 start to convey more than their proper amount of heated air whereby the suction through such pipcsis materially increased,

then some of the incoming air will pass up between the casings 20 and 32 and through the annular openings d3 around the pipe sections 30, thereby reducingthe amount of heated air passing through the sections 30.

This arrangement, therefore acts as an equalizer to tkeep the rooms heated by thef-urnace at a uniform temperature regardless of extraneous conditions such as the direction of the wind. It is contemplated that there will be one of the compartments previ ously referred to-in association with a hot air supply pipe for. each ro om of the building. 'The cold air when it leaves the surface of the water in the troughis thus divided into portions corresponding to the rooms so that the hot air for each room issep'ar rately heated. Moisture is taken by the air heforethe latter is heated which adds considerably to the heat absorption property of the air. The entrance into the draft flue 66 is located near the center of the combustion chamber and is so arranged that the smoke and. flame first pass to=the top of the com bustion chamberbefore they enter. the fiiiel on their wayto the chimney. This action tends toburn' the gases morecompletely and also forces the gases and flame into direct contact with the radiating surface formed by the casing 12 which surrounds the combustion chamber. I

1. In a hot air furnace, the combination of an outer casing. surrounding and Spaced from the. furnace. casing and sealed at the bottom, inner and intermediate concentric casings interposed betweensaid outer casing and the furnace casing, said inner and intermediate casings stopping. short ofthe bottom ofthe furnace, means for supplying coldair to the space betweensaid outer and intermediate casings, hot air pipes secured around. openings in. the upper portion of said intern'iediate casing, and pipe sections secured around openings in the upper portion of said inner casingysai'd pipe sections extending into said hot air pipes respectively and being internally spaced therefrom whereby passages are providedfrom the space between said intermediate and inner casings into said hot air pipes;

2." In a hot air furnace, the-combination of an outer casing: surrounding and spaced from the furnace casing and: sealed at the bottom, inner and. intermediate concentric casings interposedbetweenvsaidouter casing andthe furnace casing, saidinner and;intermediate casings stopping short of the:- bottom of the furnace,' a-cold air pipe leading into the :upperportion of the. space between I portion of said intermediate casing, and

pipe sections secured around openings in the upper portion of said inner casing, said pipe sections extending into said hot air pipes respectively and being internally spaced therefrom whereby passages are provided from the space between said intermediate and inner casings into said hot air pipes.

3. In a hot air furnace, the combination of an outer casing surrounding and spaced from the furnace casing, a water trough around the lower end of the furnace casing and with which the lower end of said outer casing makes a tight fit, inner and intermediate concentric casings interposed between said outer casing and the furnace casing, said inner and intermediate casings stopping short of said water trough, means for supplying cold air to'the space between said outer and intermediate casings, hot air pipes secured around openings in the upper portion of said intermediate casing, and pipe sections secured around openings in the upper portion of said inner casing, said pipe sections extending into said hot air pipes respectively and being internally spaced therefrom whereby passages are provided from the space between said intermediate and inner casings into said hot air pipes.

t. In a hot air furnace, the combination, of an outer casing surrounding'and spaced from the furnace casing and sealed at the bottom, inner and intermediateconcentric casings interposed between said outer casing and the furnace casing, said inner and intermediate casings stopping short of the bottom of the furnace, radially extending partitions between said inner casing and the furnace casing, means for supplying cold air to the space between said outer and intermediate casings, hot air pipes secured around openings in the upper portion of said intermediate casing, and pipe sections secured around openings in the upper portion of said inner casing, said pipe sections extending into said hot air pipes respectively and being internally spaced there-from whereby passages are provided from the space between said intermediate and inner casings into said hot air pipes.

5. Ina hot air furnace, the combination of an outer casing surrounding and spaced from the furnace casing and sealed at the bottom, inner and intermediate concentric casings interposed between said outer casing and the furnace casing, said inner and in termediate casings stopping short of the bottom of the furnace, conical top members for said outer, inner, and intermediate casings, a cold air pipe leading into the apex of said outer casing and directly over the apex of said intermediate casing whereby the incoming air is caused to spread'out, hot air pipes secured around openings in the top member of said intermediate casing, and pipe sections secured around openings in the top member of said inner casing, said pipe sections extending into said hot air pipes respectively and being internally spaced therefrom whereby passages are provided from the space between said intermediateand inner casings into said hot air P pe 6. In, a hotair furnace, the combination of an outer casing surrounding and spaced from the furnace casing and sealed at the bottom, inner and intermediate concentric casings interposed between said outer casing and the furnace casing, said inner and in termediate casings stopping short of the bottom of the furnace, means for supplying cold air to the space between said outer and intermediate casings, hot air pipes secured around openings in the upper portion of said intermediate casing, pipe sections secured around openings in the upper portion of said inner casing, said pipe sections extending into said hotair pipes respectively and being internally spaced therefrom whereby passages are provided from the space between said intermediate and inner casings into said hot air pipes, and a smoke flue whose upper end is centrally disposed in the combustion chamber and which inclines downwardly to the furnace casing and passes horizontally through said inner, intermediate and outer casings.

In testimony whereof I hereunto aifix my signature.

FRANK A. CONRAD. 

